Definition
In chemistry, “adhesion” refers to the the tendency of some substances to adhere to other substances. The term comes from the root words “ad” meaning “other” and “hesion” meaning “to attach”. Adhesion is usually caused by interactions between the molecules of the two substances. When applied to the biology, adhesion generally refers to the process through which cells interact with one another.
Adhesion in biology
Water molecules
The The most important adhesive substance on Earth is water. Water molecules are highly polar, which means that a part of the water molecule is very polar. molecule has a slight negative charge, while the other has a slight positive charge.
These properties allow water to interact strongly with any other charged or polar substance. Because atoms of opposite charges actively attract each other, different parts of water molecules are attracted to both positive and negative ions and molecules. On a large scale, this means that water will stick to many substances.
The Water molecules also stick together for the same reason.because all water molecules are polar. The tendency of similar (or identical) molecules to stick together is called “cohesion”.
Capillary action
I’m sure you’ve ever observed a capillary action, if you’ve ever dipped the edge of a paper napkin in a small amount of water. You will notice that the water runs up the paper napkin quite quickly, and eventually soaks the whole paper, even if you have only dipped one corner into the liquid!
This process is the adhesion of water in action: the water molecules adhere to the charged molecules inside the paper. This is the same mechanism that allows trees to extract water and minerals from the soil to nourish their leaves. Trees are made of the same materials as paper (or rather, paper is made of trees), and trees have little channels inside them that suck up water in the same way as a paper towel.
If water were not polar and did not have the property of adhesion, trees as we know them could not exist!
Cell adhesion
In order to create tissues, the cells have to interact with each other and with the extracellular environment. They do this by adhesion.
Cell adhesion involves molecules on the surface of cells called cell adhesion molecules (CAMs). These molecules interact directly with adjacent cells or may come into contact with the cell surface. extracellular matrixwhich is the network of gel-like compounds that provides support for cells throughout the cellular matrix. organism.
Cell adhesion is fundamental to the formation of multicellular organisms, as it allows for the maintenance of the structure of tissues and organs.as well as communication between cells. Cell adhesion is essential for a multitude of physiological processes, such as signalling, tissue development, cellular homeostasis and cell migration. Its dysregulation is therefore associated with a number of diseases and is therefore medically relevant. Of particular interest is the link between cell adhesion and cancer.
Cell adhesion in cancer
The cell adhesion is commonly disrupted in cancer. When the cells of a tumour have reduced cohesive properties, they can detach from the tissue and enter the circulatory system. That’s how cancer cells can migrate to other sites in the body, a process called metastasis. For example, CAMs called cadherins are often found to be dysregulated in breast cancer.
Discover more terms in our scientific dictionary here.